This invention relates to sublimation printing and particularly to a device and its novel manner of operation for transferring a sublimatible dye image or design imprinted on a transfer sheet to the surface of articles such as resin coated clay tiles, metal or paper sheet, wood and the like.
Printing through the use of sublimatible dyes is known and is rapidly becoming a more utilized process. Generally, the system involves the use of crystalline dye materials which will sublimate, that is, change from a solid to a gaseous phase without becoming liquid. These crystals are ground or pulverized to a fine particle size and then incorporated into a vehicle such as water so as to suspend and disperse the dye particles in such a manner so as to form an ink suitable for printing on a paper transfer sheet. The transfer sheet may be imprinted with such inks by any known commercial process to form the desired image or design in one or more colors. Thereafter, the transfer sheet is placed with its image side against an article having a dye receptive surface, such as a coating of resin plastic materials, i.e., polyester resin. The sheet and surface are then heated and a thermodynamic equilibrium is set up between the transfer sheet and the receptive surface which is to receive the imprinted design. The time required for effective equilibrium and thus effective transfer to occur is dependent upon known factors including the particular type of receptive coating, the dye concentration, the air gap between the sheet and surface, and the temperature of the various components. The dyes then sublimate into the surface where they condense to form the desired image on the article surface.
Many such sublimatible dyes are known as are the particular manners in which they may be utilized to form inks capable of being imprinted upon a transfer sheet and then later utilized to sublimate designs imprinted thereon to receptive surfaces. A decided advantage of this process over conventional printing is that far less sophisticated equipment is needed to effect transfer of the sublimatible design to the receptive surface once the transfer sheet has been printed by conventional processes. Accordingly, a transfer sheet may be imprinted using expensive printing processes at a central location and then the transfer sheets distributed to relatively lower technology areas having less expensive equipment to effect the sublimation transfer printing. This results in an effected use of high technology expensive printing equipment. The process further enables formation of wear resistant designs and for printing many materials which cannot be adequately printed by conventional techniques.
It would be further desirable to be able to utilize such sublimation printing techniques to print the surface of decorative materials such as tiles and the like and to simultaneously provide such tiles with a decorative, three-dimensional embossed surface. Accordingly, a main object of the present invention is to provide a device which may be utilized to provide a decorative design on the surface of articles such as clay tiles and the like through the use of sublimation printing techniques.
A further object of the present invention is the provisions of a novel platen structure through which the necessary heat to effect such sublimation printing is transferred from the platen to both the transfer sheet and the surface of the tile or other article to be imprinted.
A still further object of the present invention is the provision of a novel platen construction utilizing a heat conductive press member which enables the surface of an article to be embossed while simultaneously receiving a sublimated image thereon.
These and other objects of the present invention are accomplished by the provision of a platen having a press member comprising liquid heat-conductive metal disposed within a recess in such platen and a flexible member spanning such recess so as to restrain the movement of such liquid metal. In this manner then, as heat is applied to the platen, it is conducted to both the transfer sheet and the article surface so as to enable sublimation of the dyes to take place and the movement and subsequent condensation of such dyes in the receptive surface.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.